1. Field of the Invention
The invention relates to an ice dispenser for a refrigerator and more particularly to measured dispensing of ice pieces and sensing of dispensed ice pieces.
2. Description of Related Art
Ice dispensing systems for use in a home refrigerator are commonly known. A typical ice dispensing system includes an ice storage bin for receiving and storing ice pieces from an ice maker. The ice storage bin typically has an agitator to prevent the formation of large ice chunks. When a user requests ice, rotation of the agitator also functions to move ice pieces through an opening in the ice storage bin to be dispensed through a chute. The dispensed ice is usually in the form of ice cubes, crushed ice, shaved ice, or crescent-shaped ice. The ice dispensing system may be disposed within the freezer compartment of the refrigerator or may be mounted in a refrigerator closure member or door. U.S. Pat. No. 6,082,130, to Pastryk et al. is an example of a prior art ice dispensing system that is mounted in a refrigerator closure member or door.
One problem with conventional ice dispensing systems is the inconsistency of the ice dispensing. The refrigerator may initially dispense one cube and then suddenly dispense several cubes, which is undesirable for a user. This problem is especially manifested when dispensing crescent-shaped ice pieces. The elongated form of crescent-shaped ice pieces results in a number of orientations of the ice pieces in the storage bin. The different orientations make it difficult to consistently transfer ice pieces from the storage bin to the dispensing chute. Additionally, the orientation of the crescent-shaped ice pieces in the chute can lead to jamming in the chute, in which case ice pieces cannot be dispensed. Several dispensing methods have been explored in the prior art to address this problem.
For example, U.S. Pat. No. 6,607,096, to Glass et al. discloses a volumetric ice dispensing and measuring device for use in a beverage dispensing machine. As illustrated, ice is moved from an ice bin by a paddle through a chute when a door is opened. When passing through the chute, the ice displaces a measuring wheel. A sensor monitors the rotation of a measuring wheel by observing pulses of light broken by teeth of the wheel. One rotation of the wheel correlates to a pre-determined volume of ice to be dispensed. A control system is connected to the sensor and shuts the door to the ice bin when the sensor determines that the correct volume of ice has been dispensed. One disadvantage of this system is that there is no assurance that an accurate quantity of ice is dispensed. Since the sensor only monitors the rotation of the wheel and not the ice, the wheel may not have ice in it, but the sensor would still count a rotation as having dispensed ice. Furthermore, the sensing system comprises an additional moving part in the measuring wheel. Moving parts add complexity to the design and manufacturing of the system and potentially decrease its reliability.
Another ice dispensing apparatus is disclosed in U.S. Pat. No. 3,075,363, to Conto. The design shown in Conto comprises an ice-collecting wheel mounted in a beverage dispensing machine. A motor drives the ice-collecting wheel and as the wheel rotates, each spoke collects a volume of chipped ice. The volume of ice contained in the spoke is then dispensed through an opening. This design is not well suited for the dispensing of cubed ice. The spokes of the wheel can cause the system to become jammed due to variation in the shape of the ice. Additionally, there is no assurance that ice will be dispensed.
Finally, U.S. Pat. No. 4,942,979, to Linstomberg et al. discloses an ice dispensing apparatus that utilizes a helical structure to dispense discrete quantities of ice pieces. The helical structure separates the ice pieces and is rotated for a period of time to dispense a pre-selected volume of ice pieces. One disadvantage of this invention is in the amount of space required in the ice dispenser to house the helical structure and driving mechanism. Additionally, there is no assurance that an accurate quantity of ice is dispensed.
As can be seen, the above mentioned patent references lack an ability to detect whether or not ice has in fact been dispensed. Although the designs seek to separate and dispense a predetermined quantity of ice, there is no assurance that a user will obtain the desired quantity. Ice chunks in the storage bin as well as the orientation of ice pieces could prevent ice from being dispensed in the desired quantity. Therefore, an improvement over the prior art would be to detect whether or not an ice piece has been dispensed and to count the ice pieces as they are dispensed.
Another disadvantage of the prior art ice dispensing systems is in the metering device. Systems that utilize a sorting wheel or helical structure can become jammed due to ice chunks and the various orientations of the ice pieces. Therefore, an improvement over the prior art would be a metering device that is less likely to become jammed during operation.